In his first-ever interview, the sole Australian survivor of the Waco siege has revealed to 60 Minutes what really took place during the 51-day stand-off, and why he believes crazed cult leader David Koresh will one day return to Earth as the son of God.

Accused pedophile played boys porn: court

Grainy porn movies depicting gang bangs were shown to victims of a pedophile former teacher while they were holidaying with him at a weatherboard shack which was one bed short of their requirements, a court has heard.

This meant one of the boys was forced to share a bed with Neil Albert Futcher, and the first of his alleged victims to give evidence at his Sydney District Court trial is expected to say this is when he began preying on the young pupils.

"The accused has a sexual interest in boys," prosecutor Giles Tabuteau told the jury as he opened the crown case on Tuesday afternoon and foreshadowed expected victim evidence.

The alleged abuse of students, aged from 11 and 15 at the time, began when Futcher was in his late twenties and continued through his early thirties, the court heard.

He was working as a teacher and cricket and rugby coach at a church-run prep school at Strathfield between 1974 and 1978.

But an investigation wasn't started until 2013 and was another two years until Futcher was eventually charged.

As harrowing details of Futcher's alleged sex crimes, which allegedly includes a threesome with two boys, were detailed to the jury the now 69-year-old sat calmly in the dock taking notes.